Reanalysis of Purvis (1993) data on reported giving vs. actual missions giving as a result of a STM experience.

Purvis (1993) surveyed 79 short-term volunteers from the 38 churches of the Caldwell/Lyon Baptist Association (sub-group of the Kentucky Baptist Convention) who had gone on short-term mission trips to Brazil and Kenya. 68 participants responded to a post-trip survey and 24 were interviewed before, immediately following and six months after returning from their trip. Purvis concluded that “volunteers experienced a positive impact in mission giving, mission knowledge, attitude towards career missionary service, and view of future short-term service (p. i).”

Purvis found that 76% of respondents claimed that their missions giving had either increased greatly or some. He then triangulated these answers with 13 years of mission’s giving records from these 38 churches and reported that their giving had increased by 66.8% from 1981 until 1992. However, Purvis did not adjust for inflation. After adjusting for inflation, giving increased only 7% over 11 years or 0.7% a year. In addition, 89% of the participants were given subsidies amounting to half the cost of their trip by the association, funds which I would assume came out of this same missions’ fund—so the total amount given to the mission fields may have actually gone down substantially over these years. Finally Purvis found that

Surprisingly, [growth in] resident membership showed a low correlation (.40) to partnership missions [short-term] volunteers. After considering the matter, one realizes that cross-cultural partnerships take place outside the “church field.” So, little direct impact on resident membership results in the sending church from partnership missions experiences.

In summary, Purvis found (though he was not completely aware of it) that while the short-term missions participants believed that the impact of the trip had significantly impacted their giving, this was not the case. In fact, giving to overseas missionaries may have decreased and sadly, their participation did not result in growth in their home churches. This despite the fact that this short-term missions effort enlisted a staff person to promote the work, produced a monthly newsletter and represented a twelve-year partnership between the churches in Kentucky and the churches in Kenya and Brazil.